Head suspensions, as used to suspend magnetic read/write heads over rotating disks in disk drive units, are well known and in widespread use. A head suspension is typically constructed from multiple components of varying thicknesses such as a load beam, a spring/hinge, a flexure, a base plate, and an actuator arm. The head suspension is manufactured by welding together two or more of these components by a series of spot welds. Lasers are often used to form the welds. Methods for welding together components of a head suspension are disclosed, for example, in U.S. Pat. No. 6,417,995 to Wu et al. and U.S. Pat. No. 6,900,966 to Xu.
Variations in thicknesses between components can present complications because the amount and/or duration of energy required for melting an area on a relatively thick component will be more than that required for melting an equivalent area on a relatively thin component. As such, welding thin component(s) to relatively thick component(s) requires increased laser energy per pulse delivered to the work piece for ensuring a proper weld. In general, the greater the amount of energy needed to form the weld, the greater the likelihood of detrimental consequences such as heat-induced deformation in the relatively thinner components, edge warping, dielectric and/or coverlay burning, increased levels of soot and splatter requiring more frequent cleaning of the welding system, increased molten weld pool resulting in larger weld diameter and material flow, and weld inconsistencies. Larger weld diameters reduce the real estate available for clamping and routing traces, and decrease product and flexure design flexibility
There remains, therefore, a continuing need for methods utilizing less welding energy for welding together head suspension components. A method capable of producing weld spots of smaller size, especially in applications involving the welding of a relatively thin component to a relatively thick component, would be advantageous.